Provide a default output encoding

Set a class attribute on the App to force the input/output
encoding in case neither stdout nor getdefaultencoding() have
a valid value. This case comes up sometimes under test runners
that capture stdout, without setting up a proper encoding
for the stream capture buffer.

Change-Id: Iab1d0b1549e1d00f64ef36765852261c108e0388

2 files changed, 32 insertions, 1 deletions

diff --git a/cliff/app.py b/cliff/app.py
index 261c5cc..5cbd195 100644
--- a/cliff/app.py
+++ b/cliff/app.py
@@ -61,6 +61,7 @@ class App(object):
     LOG_FILE_MESSAGE_FORMAT = \
         '[%(asctime)s] %(levelname)-8s %(name)s %(message)s'
     DEFAULT_VERBOSE_LEVEL = 1
+    DEFAULT_OUTPUT_ENCODING = 'utf-8'
 
     def __init__(self, description, version, command_manager,
                  stdin=None, stdout=None, stderr=None,
@@ -85,7 +86,10 @@ class App(object):
             # works around a problem with Python 2.6 fixed in 2.7 and
             # later (http://hg.python.org/cpython/rev/e60ef17561dc/).
             lang, encoding = locale.getdefaultlocale()
-            encoding = getattr(sys.stdout, 'encoding', None) or encoding
+            encoding = (getattr(sys.stdout, 'encoding', None)
+                        or encoding
+                        or self.DEFAULT_OUTPUT_ENCODING
+                        )
             self.stdin = stdin or codecs.getreader(encoding)(sys.stdin)
             self.stdout = stdout or codecs.getwriter(encoding)(sys.stdout)
             self.stderr = stderr or codecs.getwriter(encoding)(sys.stderr)
diff --git a/cliff/tests/test_app.py b/cliff/tests/test_app.py
index 57256ee..5f13007 100644
--- a/cliff/tests/test_app.py
+++ b/cliff/tests/test_app.py
@@ -264,6 +264,33 @@ def test_output_encoding_default():
             assert data == actual
 
 
+def test_output_encoding_cliff_default():
+    # The encoding should come from cliff.App.DEFAULT_OUTPUT_ENCODING
+    # because the other values are missing or None
+    if sys.version_info[:2] != (2, 6):
+        raise nose.SkipTest('only needed for python 2.6')
+    data = '\xc3\xa9'
+    u_data = data.decode('utf-8')
+
+    class MyApp(App):
+        def __init__(self):
+            super(MyApp, self).__init__(
+                description='testing',
+                version='0.1',
+                command_manager=CommandManager('tests'),
+            )
+
+    stdout = StringIO()
+    getdefaultlocale = lambda: ('ignored', None)
+
+    with mock.patch('sys.stdout', stdout):
+        with mock.patch('locale.getdefaultlocale', getdefaultlocale):
+            app = MyApp()
+            app.stdout.write(u_data)
+            actual = stdout.getvalue()
+            assert data == actual
+
+
 def test_output_encoding_sys():
     # The encoding should come from sys.stdout because it is set
     # there.